Seat belt retractors are generally mounted within bodyside pillars of a vehicle, for example, inside an enclosure formed within a vehicle pillar. To connect a seat belt residing in an interior of the vehicle with the retractor mounted inside the pillar, an opening is provided in the pillar. Newer seat belt retractor designs are much larger than previous designs, in order to accommodate enhanced protective features such as adaptive pretensioners and load management features. These newer retractors may require relatively larger openings in the “B” pillar to install the retractor, resulting in a reduction in the cross-sectional area of the portion of the pillar incorporating the opening. Thus, during roof crush and side impact events, relatively greater stresses are produced in the portion of the pillar having the reduced cross-sectional area.
To address this problem, a separately formed reinforcement ring is attached to an edge of the opening in some vehicle designs in order to structurally reinforce the reduced cross-section. However, due to the increased size of the new seatbelt retractors, there is often insufficient package space to efficiently and securely weld additional reinforcement rings around the opening. Also, inclusion of the reinforcement ring and installation of the ring in the restricted space described above increases the piece part and assembly costs of the pillar assembly. Thus, a need exists for a method of reinforcing the cross section of a pillar assembly in the region of a retractor opening incorporated into the pillar.